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. Author manuscript; available in PMC: 2019 Nov 8.
Published in final edited form as: J Invest Dermatol. 2019 Jun 15;139(11):2263–2271.e5. doi: 10.1016/j.jid.2019.03.1163

Figure 4. RAS-MAPK pathway is activated in keratinocytes during squamatization.

Figure 4.

(a) Immunohistochemical staining demonstrates that basaloid keratinocytic cells typical of BCC, such as those contained in the dashed box, have minimal expression of p-ERK, whereas squamatized keratinocytes and adjacent basaloid cells, such as those contained in the solid box, show high expression of p-ERK. Left panel, H&E staining original magnification ×20. Right panel, p-ERK staining, original magnification ×20. Bar = 50 μm. (b) Representativepicturesofthe H&E, DAPI, nuclear Gli1 (as readoutfor Hh pathwayactivation) and p-MEK (as readout for Ras/MAPK pathway activation) immunostainings in human BSC samples. Higher magnifications of the basal and squamous areas of the tumor are shown in the top left and top midline framed pictures, respectively, with nuclei highlighted by white dashed lines. Basaloid keratinocytic cells typical of BCC have a higher expression of nuclear Gli1 and low p-MEK, whereas squamatized keratinocytes have high p-MEK and low Gli1. BCC, basal cell carcinoma; BSC, basosquamous carcinoma; H&E, hematoxylin and eosin; Hh, Hedgehog; MAPK, mitogen-activated protein kinase; SCC, squamous cell carcinoma. Bar = 25 μm.